Design of Plate-type Actuator using SMA Wire for Assistant Artificial Heart Muscle

A compact thin plate-type actuator using Ti—Ni—Cu shape memory alloy (SMA) wire is proposed and designed for its optimized motion to be applied as an assistant artificial heart muscle. The artificial heart muscle will assist by pushing weakened cardiac muscle that has been damaged by myocardial infarction and has lost its ability to contract. The actuator consists of a SMA wire, 250 μm in diameter, and a leaf spring that acts as a bias spring and cooling plate. The SMA wire is fixed at the end of the leaf spring to transform contraction motion into bending of the actuator. The shape of the actuator is controlled by on/off control of electric current applied via the SMA wire. Repeatable bending and releasing will be utilized for the heart assist application. This repeatable actuator motion will be able to assist up to 120 bpm (heartbeats per minute).